An organic electroluminescence (hereinafter, referred to as “organic EL”) display device includes a light emitting element provided in each of pixels and displays an image by controlling light emission of each of the light emitting elements independently. The light emitting element has a structure in which a layer containing an organic EL material (hereinafter, also referred to as a “light emitting layer”) is interposed between a pair of electrodes, one of which is a lower electrode and the other of which is an upper electrode.
In such an organic EL display device, one of the electrodes is provided in each pixel as an individual pixel electrode (such an electrode is also referred to simply as a “pixel electrode”), and the other electrode is provided in correspondence with a plurality of pixels as a common pixel electrode supplied with a common potential (such an electrode is also referred to as a “common electrode”). The organic EL display device controls an electric current supplied from the individual pixel electrode in each pixel to the common pixel electrode and thus controls the light emission of the pixel.
An organic EL display device, especially, an organic EL display device realizing full-color display with a combination of a white light emitting element and color filters, generally includes an array substrate and a color filter substrate that are assembled together. The array substrate includes a plurality of light emitting elements arrayed in rows and columns. The color filter substrate includes color filters of, for example, three colors, namely, R (red), green (G) and blue (B), and a light-blocking layer (also referred to as a “black matrix”) demarcating the color filters of the three colors.
Occasionally in a display device, an R (red) pixel, a G (green) pixel and a B (blue) pixel are each used as a sub pixel, and a group of these sub pixels is used as one pixel. In such display devices, various arrangements are made on a structure of pixels including the sub pixels in order to improve the display quality.
For example, Japanese Laid-Open Patent Publication No. 2006-79104 discloses a liquid crystal display device as follows. The number of driving circuit chips is decreased to lower the production cost of the display device. In order to improve the image quality, the display device includes a plurality of pixels each including a pixel electrode and a switching element connected to the pixel electrode. The pixel electrodes of the plurality of pixels are arrayed in rows and columns. The display device also includes a plurality of gate lines connected to the switching elements and extending in a row direction, and a plurality of data lines connected to the switching elements and extending in a column direction. In each of rows, at least two gate lines extend. The pixel electrodes each include a first portion and a second portion farther from the corresponding data line than the first portion. The switching elements are each located in the vicinity of the second portion of the corresponding pixel electrode.
Japanese Laid-Open Patent Publication No. Hei 10-123508 discloses a reflection-type liquid crystal display device and a method for producing the same as follows. The display device is devised to display an image with no seam even when exposure to light is performed a plurality of times at different positions. A reflective plate and a display quality mask each include a plurality of concave-and-convex patterns, each of which corresponds to one pixel. At least one type of concave-and-convex pattern is provided in the number of two or more. Any two patterns among the plurality of concave-and-convex patterns have one or a plurality of relationships among translation, rotation and inside-out inversion. The one or the plurality of relationships include translation. The concave-and-convex patterns are located irregularly. Such a mask 1a is used to expose a photosensitive resin film to produce the reflective plate having a convexed portion and the reflection-type liquid crystal display device.